The present invention relates to thermometers, and more particularly to a thermometer for measuring the oil temperature being supplied to an internal combustion engine especially those used to power motorcycles.
The temperature of the lubricating oil supplied to an internal combustion engine is critical to the performance and life of the engine. In motorcycle applications, because they are recreational vehicles and therefore often driven fast over rough terrain and under heavy loads, the engine lubricating oil temperature can rise above 200.degree. F. It is believed that every 20.degree. F. increase in engine oil lubricating temperature reduces the lubricating quality of the oil by 50%. In addition, of course, the higher the temperature of the lubricating oil, the less is its ability to aid in cooling the engine because of improper lubricating temperature. Therefore, there is a special need in motorcycle applications for an oil temperature measuring device. However, in motorcycle applications, particularly for motorcycles used for off-the-road riding, this need is complicated somewhat by the fact that the oil temperature measuring device must be sturdy to withstand the rigors of vibration and impact as will occur when the motorcycle is driven over rough terrain or in a race.
Temperature sensing devices for measuring the temperature of oil being supplied to an internal combustion engine are known, for example, as disclosed in U.S. Pat. No. 1,678,389 issued on July 24, 1928 to A. Holmes.
However, none of the oil temperature measuring devices known to me satisfies the above-mentioned requirements for motorcycle applications.